<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>input 输入动画</title>
    <link rel="stylesheet" href="./index.css">
</head>
<body>
    <div class="form">
        <h2>登　录</h2>
        <div class="input-group">
            <div class="input-inner">
                <input type="text" required>
                <div class="underline"></div>
                <label>账号</label>
            </div>
        </div>
        <div class="input-group">
            <div class="input-inner">
                <input type="text" required>
                <div class="underline"></div>
                <label>密码</label>
            </div>
        </div>
        <div class="input-group">
            <button class="btn">登 录</button>
        </div>
    </div>
</body>
</html>
